Gelled ink vehicles are used in lithography printing ink applications. In order to function properly, the vehicle must have a gelatinous texture so that printing inks can be made from which will have low misting properties and will dry properly minimal energy applied. The gelatinous texture must be such that it is retained in the ink and does not break down when running on a high speed press. Such a vehicle, also known in the art as a varnish, is said to have a strong gel structure.
In order to provide the necessary strong gel structure, gellants are added to the ink vehicles. These gellants, such as aluminum diisopropoxide acetoacetic ester chelate (AIE-M) or oxyaluminum octoate (OAO), are added to the vehicle mix to provide for an increase in the viscosity and yield value of the vehicle, However, an excess of the gellant in the mix sometimes causes adverse side-effects in the lithographic printing process, addition, since gellants are the most expensive part of the vehicle composition, excess gellant leads to increased cost of production.
Recently, manufacturers of ink vehicles have started using so,vents from renewable resources which contribute significantly lower levels of volatile organic compounds (VOC) ink, such as various fatty acids esterified with alcohols and glycols. Such so,vents are being used as replacements for the volatile non-renewable petroleum distillates. The fatty acid ester solvents have greater solvation power over the high molecular weight resins commonly used to prepare gelled ink vehicles and the hydrotreated petroleum distillates previously used. Such increased solvency power tends to increase the difficulty in producing the desired strong gel structure while using minimal amounts of gellants.
For the foregoing reasons, there is a continual need for an ink vehicle with a strong gel structure and low VOC using renewable resources as solvents. The ink product must have low misting and good drying without excess use of energy.
It is an object of the invention to provide such a vehicle using solvents derived from renewable resources.
It is a further object to provide an ink vehicle with a strong gel structure without the use of excess gellants.